(1) Field of the Invention
This invention generally relates to enhancing receive arrays in a sonar dome.
(2) Description of the Prior Art
The current art for sonar domes is such that the sonar domes containing receive arrays are typically pressurized with sea water. The performance of sonar domes in determining the location of acoustic targets is limited in size by spacing of the receiver elements in an array. In one part, this is a function of the Nyquist-Shannon sampling theorem as applied spatially to an array of sensors. Beam width is a function of the array spacing and the speed of sound in the media. Often times, a larger aperture is necessary, and cannot be achieved due to physical limitations caused by the current sonar dome size. Accordingly, a need in the art exists for enhancing the current arrangement of receive arrays within known sonar domes.
The following patents, for example, disclose known sonar domes and reduction of cavitation, but do not disclose a solution to the need to increase the effective aperture of sonar receive arrays that are enclosed in a sonar dome. U.S. Pat. No. 4,764,909 to Darner;                U.S. Pat. No. 5,008,863 to Archibald;        U.S. Pat. No. 5,717,657 to Ruffa; and        U.S. Pat. No. 5,382,286 to Fanning et al.        
It should be understood that the present invention would provide an increased effective aperture of sonar receive arrays enclosed in a sonar dome. This is done by reducing the effective speed of sound inside a sonar dome, so that the same sized receive array is larger compared to a wavelength than it otherwise would be if the dome were simply filled with pressurized water.